A decision analysis of the effect of avoiding axillary lymph mode dissection in low risk women with invasive breast carcinoma

BACKGROUND. Evidence that avoiding axillary lymph node dissection (AxD) str ikes an appropriate balance between morbidity and recurrence risk in patien ts with invasive breast carcinoma generally is anecdotal and without a form ally quantified basis. The current study presents a decision analysis of th e difference in 5-year disease free survival (DFS) rate between treatment s cenarios with and without routine AxD. METHODS. To derive quantitative estimates of the effect of avoiding AxD on 5-year DFS, the authors examined outcomes for women undergoing 2 treatment scenarios: AxD or no AxD with adjuvant therapy decisions based on risk fact ors in the primary tumor. Eligible patients belonged to 2 lymph node metast ases risk groups: low (patients without palpable lymph nodes and lymphatic or vascular invasion [LVI] negative tumors less than or equal to 0.5 cm in greatest dimension) and moderate (patients with mammographically detected, LVI negative tumors, between 0.6-2.0 cm in greatest dimension or patients w ith palpable LVI negative tumors between 0.6-1.0 cm in greatest dimension w ith nonpalpable lymph nodes). Along with observed data regarding treatment and recurrence, the authors employed estimates of the efficacy of chemother apy, tamoxifen, and regional radiation therapy derived from published rando mized trials to estimate the 5-year DFS rate for treatment scenarios with a nd without AxD. RESULTS. Patients in the low risk group had a 5% risk of lymph node metasta ses. In these women, eliminating AxD and treating no patients with chemothe rapy and/or tamoxifen resulted in a < 1% decrease in the 5-year DFS rate. P atients in the moderate risk group had a 10% risk of lymph node metastases. Eliminating AxD and treating only those women with Grade 3 tumors > 1 cm i n greatest dimension with chemotherapy and/or tamoxifen resulted in a 1.8% decrease in the 5-year DFS rate. However, if all patients in this group wer e treated with chemotherapy and/or tamoxifen and no AxD, the 5-year DFS rat e increased by 2.7%. CONCLUSIONS. In patients with a low risk of lymph node metastases, it was e stimated that eliminating AxD may result in only minimal changes in the est imated 5-year DFS rate. Cancer 2000;88:1852-62. (C) 2000 American Cancer So ciety.